State tax filing

Son's company has locations all over US. HQ is in Denver with offices in NYS and WA. Each office pays local state employees as local. My son will be a WA employee.

 

It seems awfully aggressive to tax any business trips to NYS/NYC for a company thats not located in NY. Anyone taking a short business trip would then have to do non-resident tax return. Thats a ton of people and I'd imagine most don't file. In my son's case, company has a location in NYS/NYC but he doesn't work for them. He works for the WA office.